1. Field of the Invention
The present invention relates to a power unit for a motorcycle including an internal combustion engine which has a crankshaft rotatably supported on an engine body with a transmission having an input shaft and an output shaft arranged parallel to each other and housed inside of the engine body. A clutch for changing over the connection/disconnection of power transmission between the crankshaft and the input shaft is provided with a hydraulic cylinder for driving the clutch. A cylinder support member includes a cylindrical case portion where a portion of the hydraulic cylinder is housed and is mounted on the engine body.
2. Description of Background Art
A power unit for a motorcycle is known wherein the power unit is required to satisfy a miniaturization and a reduction in the weight of the power unit. In the power unit for a motorcycle disclosed in Japanese Patent No. 4,531,361, the miniaturization and the reduction in weight of the power unit for a motorcycle are realized by shortening an inter-axis distance between an input shaft and an output shaft of a transmission. However, on the output shaft of the transmission, a drive sprocket around which a drive chain for transmitting power to a rear wheel is wound is mounted together with a connecting mechanism for connection with a drive shaft. Further, a cover member for protecting a projecting end portion of the output shaft projecting from an engine body is mounted on the engine body. Accordingly, in arranging a hydraulic cylinder for driving a clutch near the output shaft, there is no way but to arrange the hydraulic cylinder at a position displaced from the cover member in the axial direction while avoiding the cover member. In such a structure where the hydraulic cylinder is arranged on the periphery of the projecting end portion of the output shaft in an axially displaced manner from the cover member, the power unit becomes of a large size in the axial direction of the output shaft. In view of the above, there has been a demand for the realization of a structure which suppresses the projection of the hydraulic cylinder in the axial direction.